Integrated lancing and measurement device

Abstract

An integrated lancing and measurement device is provided comprising a sensor designed to determine the amount and/or concentration of analyte in a biological fluid having a volume of less than about 1 μL. A piercing member is adapted to pierce and retract from a site on the patient to cause the fluid to flow therefrom, and the sensor is positioned adjacent to the site on the patient so as to receive the fluid flowing from the site to generate an electrical signal indicative of the concentration of the analyte in the fluid. The sensor is comprised of a working electrode comprising an analyte-responsive enzyme and a redox mediator, and a counter electrode. An analyte monitor is operatively connected to the sensor and adapted to measure the signal generated by the sensor. Also provided are analyte measuring methods that optionally employ the integrated lancing and measurement device.

1. An analyte measurement device for determining the concentration of glucose in blood from a patient, comprising:
 a sensor comprising: 
 a working electrode, a counter/reference electrode, a redox mediator, a glucose-responsive enzyme, and a polymer, wherein said working electrode, counter/reference electrode, redox mediator, enzyme and polymer are in communication with a sample chamber of the sensor having a volume of less than about 0.5 μl; and 
 a tapered tip comprising a sample application site; and 
 a coulometer. 
 
     
     
       2. The sensor of  claim 1 , wherein the sensor is in the shape of a strip. 
     
     
       3. The sensor of  claim 1 , wherein the sensor includes a sorbent material for transporting blood to contact the working and counter electrodes. 
     
     
       4. The sensor of  claim 3 , wherein the sorbent material is contained in the sample chamber. 
     
     
       5. The sensor of  claim 1 , wherein the glucose-responsive enzyme comprises a glucose oxidase or a glucose dehydrogenase. 
     
     
       6. The sensor of  claim 1 , wherein the working electrode is on a first substrate and the counter electrode is on a second substrate. 
     
     
       7. The sensor of  claim 1 , wherein the polymer is poly(4-vinyl pyridine) (PVP) or poly(l-vinyl imidazole) (PVI). 
     
     
       8. The sensor of  claim 1 , wherein the sensor further comprises a third electrode. 
     
     
       9. The sensor of  claim 1 , wherein the charge generated by the sensor by electrolysis of a buffer solution comprising no glucose is no more than about 26% of the charge generated by electrolysis of a buffer solution comprising 6 mM glucose. 
     
     
       10. The sensor of  claim 1 , wherein the charge generated by the sensor by electrolysis of a buffer solution comprising no glucose is no more than about 14% of the charge generated by electrolysis of a buffer solution comprising 10 mM glucose. 
     
     
       11. The sensor of  claim 1 , wherein the redox mediator comprises an osmium complex, a ferrocyanide, or a ferricyanide. 
     
     
       12. The sensor of  claim 1 , wherein the working electrode is constructed of a material selected from gold, carbon, platinum, ruthenium dioxide and palladium. 
     
     
       13. The sensor of  claim 1 , wherein the working electrode is separated from the counter/reference electrode by a distance of less than 200 micrometer. 
     
     
       14. A method for determining the blood glucose concentration in a patient, the method comprising:
 (a) providing a sensor comprising:
 a working electrode, a counter/reference electrode, a redox mediator, a glucose-responsive enzyme, and a polymer, wherein said working electrode, counter/reference electrode, redox mediator, enzyme and polymer are in communication with a sample chamber of the sensor having a volume of less than about 0.5 μl; and 
 a tapered tip comprising a sample application site; and 
 
 (b) determining the blood glucose concentration by coulometry. 
 
     
     
       15. The method of  claim 14 , wherein the method comprises contacting the patient with the sensor and then determining the blood glucose concentration. 
     
     
       16. The method of  claim 14 , wherein the charge generated by the sensor by electrolysis of a buffer solution comprising no glucose is no more than about 26% of the charge generated by electrolysis of a buffer solution comprising 6 mM glucose. 
     
     
       17. The sensor of  claim 14 , wherein the charge generated by the sensor by electrolysis of a buffer solution comprising no glucose is no more than about 14% of the charge generated by electrolysis of a buffer solution comprising 10 mM glucose. 
     
     
       18. An analyte measurement device for determining the concentration of glucose in blood from a patient, comprising:
 a sensor comprising: 
 a working electrode, a counter/reference electrode, a redox mediator, a glucose-responsive enzyme and a polymer, wherein said working electrode is on a first substrate and said counter/reference electrode is on a second substrate, and said working electrode, counter/reference electrode, redox mediator, enzyme and polymer are in communication with a sample chamber of the sensor having a volume of less than about 0.5 μl; and 
 a tapered tip comprising a sample application site; and 
 a coulometer. 
 
     
     
       19. The sensor of  claim 18 , wherein the charge generated by the sensor by electrolysis of a buffer solution comprising no glucose is no more than about 26% of the charge generated by electrolysis of a buffer solution comprising 6 mM glucose. 
     
     
       20. The sensor of  claim 18 , wherein the charge generated by the sensor by electrolysis of a buffer solution comprising no glucose is no more than about 14% of the charge generated by electrolysis of a buffer solution comprising 10 mM glucose. 
     
     
       21. The sensor of  claim 18 , wherein the glucose-enzyme comprises glucose oxidase or glucose dehydrogenase. 
     
     
       22. The sensor of  claim 18 , wherein the redox mediator comprises an osmium complex, a ferrocyanide, or a ferricyanide. 
     
     
       23. The sensor of  claim 18 , wherein the working electrode is constructed of a material selected from gold, carbon, platinum, ruthenium dioxide and palladium. 
     
     
       24. The sensor of  claim 18 , wherein the working electrode is separated from the counter/reference electrode by a distance of less than 200 micrometer.